ISHS Acta Horticulturae 732: VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems
CANOPY/AIR TEMPERATURE GRADIENT AS AN INDICATION OF STRESS IN CHERRY TREES |
| Authors: | G. Stoimenov, Y. Kirkova, N. Kolev, M. Gospodinova |
| Keywords: | leaf temperature, crop water stress indicator |
| Abstract:
The idea that remote sensing of canopy temperature could be a crop water stress indicator is not new. Since 1962, the difference between canopy and air temperature has been used as a stress indicator for different crops, including maize, sunflower, soybean, cowpea, millet, barley, squash, and forage crops. However, for orchard trees, where evapotranspiration patterns are different, little research in this area has been done. This paper describes a lysimeter experiment with three soil types: alluvial-meadow soil, sinnamonic forest soil, and smolnitza soil. One cherry tree (cv. Stella) from the Belgium serya Grand Manil (GM9 – Inmil) was planted in each lysimeter cell. Tensiometers and gypsum blocks, installed at 20, 40 and 70 cm depths and four distances from the tree were used to measure soil water potential (SWP) and soil water content (SWC), respectively. An infrared thermometer (IRT) was used to measure tree and soil surface temperature at 1300 h during vegetative growth in 2000. The difference in tree and air temperature was calculated. An infrared gas analyser LCA – 4ADC (GB) was used to measure photosynthesis (Pn) and transpiration (TR). Tree were drip irrigated, and total irrigation was 83.11 mm. The 2000 growing season was marked by high temperatures, low relative humidity and below average precipitation for the Plovdiv region. Relationships between canopy temperature minus air temperature (dT = Tc – Ta) and soil water potential (SWP) were observed, with R2 > 0.65. The relationships between dT and soil water content (SWC) exhibited R2 > 0.58. There was a trend towards higher R2 values at distances closer to the tree. | |
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